Distal renal tubular acidosis in polyarteritis nodosa.

Distal renal tubular acidosis developed in a patient with polyarteritis nodosa. The acidosis gradually disappeared, together with most of the other symptoms of systemic vasculitis, after treatment with prednisone and cyclophosphamide. Tubular function test results in this patient suggested that the mechanism underlying the acidification disturbance was acid back-leakage.